Efficacy of Argel (Solenostemma argel (Del) hayne) Shoots’ Extract in the Control of the Red Flour Beetle (Tribolium castaneum Herbst)

Abstract

Laboratory studies were conducted to evaluate the efficacy of
aqueous and organic extracts of the argel (S. argel) shoots against the 4th
larval instar and adult stages of the red flour beetle (Tribolium castaneum)
in the Sudan. Argel shoots were extracted sequentially by organic solvents
of increasing polarity (petroleum ether, ethyl acetate and ethanol) as well
as directly by distilled water or ethanol. Extracts were tested at
concentrations ranging between 1% and 10%. The evaluated efficacy
parameters were mortality, repellency and antifeedant effects. The tests
were conducted in Petri dishes (9 cm i.d) and plastic cups (capacity 200
ml) and the obtained data were subjected to the analysis of variance and to
the probit analysis. The results of the mortality data indicated that
petroleum ether extracts was the most potent against the 4 th larval instar of
T.castaneum as shown by its low LD50 of 8.2%, while ethyl acetate
extract was the most potent against the adult of this pest with an LD50
value of 16%. The results showed that various types of argel shoot
extracts induced significant dose dependent repellency against the
T. castaneum. The highest 24 hours repellency was caused by the
petroleum ether extract on the adult stage of T. castaneum as indicated by
its low ED50 value of 1.58%.The different argel shoot extracts induced
significant antifeedant action against the test insect. The lowest feeding
ratio (0.02) was recorded in ethyl acetate extract- treated crushed wheat
grains